Head ditch hydraulics and the variability of inflows to irrigation furrows

Smith, R. J. and Gillies, M. H. (2010) Head ditch hydraulics and the variability of inflows to irrigation furrows. Irrigation and Drainage, 59 (4). pp. 442-452. ISSN 1531-0353

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The spatial variability and temporal variation of furrow inflows have a major impact on the performance of furrow irrigation, as indicated by the usual measures of application efficiency and uniformity. They also cause difficulties in determining the soil infiltration characteristic through inverse solution techniques and in selecting preferred values for the operational variables of flow rate and time to cut-off to give maximum performance at the field scale.

In this paper a steady spatially-varied flow analyses is performed to predict the steady water surface profiles in a typical head ditch and the subsequent spatial variability of the furrow inflows, for both pipe or siphon and sill or bank-less type water application systems. The resulting patterns were very similar to those seen in the spatially varied pipe flow in gated pipe, with depths and outflows increasing toward the downstream end of the channel. It is shown that it is feasible to design head ditches to minimise the variability in outflows. An unsteady analysis of the same head ditch illustrated the variation of outflows with time caused by the time taken to fill the channel.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Author version deposited in accordance with the copyright policy of the publisher.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 09 Jan 2011 06:55
Last Modified: 03 Jul 2013 00:06
Uncontrolled Keywords: unsteady flow; steady spatially-varied flow; furrow irrigation; siphon
Fields of Research : 07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070105 Agricultural Systems Analysis and Modelling
09 Engineering > 0999 Other Engineering > 099901 Agricultural Engineering
07 Agricultural and Veterinary Sciences > 0799 Other Agricultural and Veterinary Sciences > 079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)
Socio-Economic Objective: D Environment > 96 Environment > 9609 Land and Water Management > 960905 Farmland, Arable Cropland and Permanent Cropland Water Management
E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: 10.1002/ird.495
URI: http://eprints.usq.edu.au/id/eprint/9032

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